With increasing numbers of NIH funded investigators using animal models to study molecular mechanisms and treatment of diseases, there is a compelling need to image tissue structure and function in situ, in vivo, over time without damaging tissue. The major system-related limitation of LSCM imaging of living tissues is photodamage caused by the intense laser illumination and limited depth penetration of the laser beam. Two photon laser scanning microscope (TPLSM) technology overcomes these limitations. TPLSM is fast becoming the imaging method of choice to study fundamental biological processes in living animals. Our preliminary data demonstrated that the two photon microscopy can be successfully used on the living mouse after stroke. We request funds to purchase a Radiance 2100 AG-2Q Confocal Multiphoton System to be employed in an array of NIH funded grants, including 3 P0ls. The new system will be utilized for studies of molecular and pathophysiological mechanisms underlying thrombosis, blood brain barrier disruption, angiogenesis, axonal and dendritic plasticity, brain tumor, chondrocyte apoptosis, and hypertension. Imaging changes in immunofluorescent signals and green fluorescent protein (GFP) signals are a critical part of each of these N IH funded grants. The use of Radiance 2100 AG-2Q Confocal Multiphoton System will allow investigators to greatly expand their proposed experiments to image changes in tissue structure and function in situ over time without damaging or sectioning tissue. This will greatly augment to accomplishments of these funded grants and research at Henry Ford Health Science Center as well as provide a major resource to the research community in Metropolitan Detroit. Furthermore, data obtained from the Radiance 2100 AG-2Q Confocal Multiphoton System will provide new insights into mechanisms underlying our proposed studies, permitting us to generate new hypotheses to be tested in grant renewal and new grant applications.